External Apache Directives

I'm trying to add some items inside the Apache directives but when I try to save the site details page the text is truncated.

I admit that I have paste about 3000 rows inside it because we have a customer with thousands of domains that redirect only in one site. So I thought to ask you if there is a way to create an external file to attach to the apache directives.

Is it possible?

These are only two domains that I redirect to the main php controller folder: